In many parts of the world fresh, potable water is not readily available or plentiful. Ironically, many of these regions are surrounded by, or have access to, virtually limitless amounts of water that is not potable because of salinity (e.g., sea water), or other mineral contaminants (e.g., brackish water).
This problem has been recognized for a long period of time, and various approaches to generating potable and, more preferably, distilled water, abound in the field. See, e.g., U.S. Pat. No. 7,955,478 describing what is referred to as a “vertical, tubular evaporation apparatus.” The invention described in this patent shows that Fresnel lenses, which are a feature of one embodiment of the invention, can be used in the preparation of distilled water. The devices depicted in the '478 patent include inner an outer cylinders but do not disclose a vacuum element therebetween.
Many approaches to the field of preparing distilled water from sea water employ solar energy. See in this regard, U.S. Pat. Nos. 5,468,351 and 4,749,447, which also discuss the use of Fresnel lenses. Also teaching solar power based distilling apparatuses are U.S. Pat. Nos. 4,194,949; 4,160,523; 3,960,668; 3,232,846; 2,412,466; and 2,332,294, all of which are incorporated by reference.
Notwithstanding the interest shown, e.g., by the prior art, in apparatuses that are useful for separating impurities such as salt and other minerals from impure water, there is still a need for simple, effective devices which utilize as little energy as possible, and can also operate continuously.
It is an object of the invention to address all of these issues. How this is accomplished will be seen from the disclosure which follows.